Acquisition - Summary of Pro Forma Information Related to Results of Operations (Detail) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	May 31, 2014	May 31, 2013	May 31, 2014	May 31, 2013
Net sales:
As reported	$ 403.1	$ 286.6	$ 732.8	$ 530.3
Net (loss) income:
As reported	(50.2)	(11.8)	(52.3)	(25.8)
Rocketdyne Business [Member]
Net sales:
As reported		286.6		530.3
Pro forma		489.0		909.9
Net (loss) income:
As reported		(11.8)		(25.8)
Pro forma		$ 1.4		$ 13.5
Basic (loss) income per share
As reported		$ (0.20)		$ (0.43)
Pro forma		$ 0.02		$ 0.22
Diluted (loss) income per share
As reported		$ (0.20)		$ (0.43)
Pro forma		$ 0.02		$ 0.21